Hardness and tensile strength study on Al356–B₄C composites

Abstract

Additions of high modulus particles to aluminium alloys offer the potential to develop a lightweight composite with high strength and hardness. Al356 matrix composites reinforced with B4C particles were prepared using stir casting method. Hardness and tensile strength of unreinforced alloy and composites with different volume percentages of boron carbide particles were measured and compared. Microstructural characterisation revealed an almost uniform distribution of the B4C particles in the matrix. It also showed that the grain size of aluminium composite is smaller than that of monolithic aluminium. X-ray diffraction studies also confirmed the existence of boron carbide and some other reaction products, such as AlB2 and Al3BC, in composite samples. It is observed that the mechanical properties enhance with increasing particle fraction. The great enhancement in values of ultimate tensile stress and hardness observed in this experiment is due to small particle size and good distribution of the B4C particles, which was confirmed by SEM images. According to the results of this experiment, quite significant improvement in strength is noted when 10 vol.-B4C particles is added; a further increase in B4C content leads to a reduction in strength values. This might be the result of greater agglomeration of particles and higher degree of microporosity present in the composite at higher B4C content.

Sol–gel coated B4C particles reinforced 2024 Al matrix composites

“…Boron carbide is an attractive ceramic reinforcement for a range of application including wear components, mechanical seals, aerospace parts, and cutting tools because of its high impact and wear resistance, low density, high melting point, and excellent resistance to chemical agents as well as high capability for neutron absorption. Further, its density (2.52 g/cm 3 ) is very close to that of Al alloy matrix [9,12].…”

“…Iron may be present either as iron or as iron oxide. It is reported that iron might get oxidized during this process and oxide layers, in particular Fe 2 O 3 layers generated during wear, act as solid lubricants and help to reduce the wear rates [3,[28][29][30]. It is noted that the debris of the composites with coating are associated with the formation of more iron-rich layers on the contact surfaces.…”

“…The wear resistance of aluminium alloys is improved as a consequence of the incorporation of ceramic fibres or particles which act as the load-bearing and abrasive member [3][4][5][6]. The application of ceramic particle-reinforced aluminium alloy matrix composites in automotive and aircraft industries is gradually increasing in the case of pistons, cylinder heads, connecting rods, etc.…”

Manufacturing of B4C particle reinforced A360 aluminium cellular composite materials by the integration of stir casting and space holder methods

“…The studies on alloy A356 reinforced with B 4 C and Al 2 O 3 particles showed that ceramic particle addition enhanced hardness and tensile strength of the materials. 15,16 This improvements on mechanical properties are interpreted as grain refinements due to the addition of hard ceramic particles. 16 The reinforcement with B 4 C particles of wrought aluminium alloys such as 7075, 6061 showed also similar results.…”

Mechanical Properties as a Function of Casting Process of Aluminum–Silicon Alloy Matrix Composites

“…Therefore, depending on the overall effect of all the factors involved, the behavior of the composite form change will be different. This non-conformance stress also depends on the temperature at which the composite cools [15][16][17]. It should be borne in mind that although the thermal inconsistency stress will increase the strength, this increase is not very high in composite particles.…”